This application claims the benefit of Korean Application No. 75932/1997, filed Dec. 29, 1997, in the Korean Patent Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a data write operation in an optical disk drive, and more particularly, to a method and apparatus for recording an optical disk in the event of a buffer-underrun possibly generated during a data write operation.
2. Description of the Related Art
In optical recording and reproduction technology using a laser, a data read operation is performed by sensing a variation in the intensity of a laser beam reflected from a data recording surface of an optical disk. Methods of changing the intensity of reflected light, that is, for writing data on an optical disk, include using interference between concave pits formed on a disk and a reference plane (general CD: Compact Disk or DVD: Digital Video Disk or Digital Versatile Disk), changing the polarity of a magneto-optical recording medium (magneto-optical disk), using the intensity of reflected light varied according to the state of a recording layer as in a phase-change disk (CD-RW: CD-ReWritable), and changing the state of organic pigment (CD-R: CD-Recordable). CDs using such methods can be grouped into a reproduction-only type (general CD), a recordable-once type (CD-R), and a rewritable type (CD-RW), according to reproducibility and recordable times. For example, a user can write data once on a CD-R, and plural times on a CD-RW.
An optical disk drive with a data recording capability should be provided in order to write data on a CD-R or a CD-RW. Hereinafter, an optical disk or a disk refers to either the CD-R or the CD-RW.
In a data write operation, the optical disk drive stores write data received from a host computer such as a personal computer (PC) in a buffer, and writes the stored data on a disk when the buffer has a predetermined amount of data. Because the amount of the data received from the host generally exceeds the capacity of the buffer, the optical disk drive simultaneously implements data storage in the buffer and data write on the disk. A possible stoppage or delay of data transmission from the host computer during the data write operation leads to a stoppage or delay in storing data in the buffer, in turn. Thus, the optical disk drive continues writing the data until the buffer is empty. This is termed a buffer-underrun. The buffer-underrun may also be caused when the data recording rate of the optical disk drive is faster than the data transfer rate of the host.
The interruption or delay of data transmission from the host, resulting in the buffer-underrun, can be attributed to multi-tasking or communication in the host computer during a write operation.
Upon occurrence of a buffer-underrun during a data write operation on a CD-R or CD-RW, the optical disk drive outputs a signal indicative of the buffer-underrun to the host computer and stops the write operation. Since the optical disk drive modulates and scrambles input data by a predetermined amount in a predetermined write format prior to writing, the optical disk drive cannot locate the recording end of data on the disk in the event of the buffer-underrun. Therefore, even if the host computer locates the latest recording data from source data and transfers the following as write data, a blank space is produced or overlapped recording of the write data occurs in an unrecorded area of the partially recorded disk. As a result, the data write operation produces errors.
Upon occurrence of the buffer-underrun during a data write operation, the CD-RW is made to be rewritable from the beginning of the CD-RW, while the CD-R cannot be reused and should be discarded.
Accordingly, it is an object of the present invention to provide a method of automatically recording write data on an optical disk even during a buffer-underrun in an optical disk drive.
It is another object of the present invention to provide a method of recording write data on an optical disk even during a buffer-underrun in an optical disk drive, which enables reuse of the optical disk.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and other objects of the present invention, there is provided a method of recording source data on an optical disk during buffer-underrun in an optical disk drive. In the method in the optical disk drive which buffers source data received from a host computer and writes the source data on the optical disk, it is determined whether the optical disk is a CD-R (Compact Disk-Recordable) or a CD-RW (CD-ReWritable), an address next to a current recording end of data is detected upon occurrence of a buffer-underrun, if the optical disk is a CD-R, the detected address is designated as a program start address of the optical disk, a signal indicative of the buffer-underrun is transmitted to the host computer, the host computer re-transmits the source data to the optical disk drive, and then the source data is re-written on the optical disk, beginning from the program start address.